Ellipsograph



.1. H. BARKER 2,623,286

ELLIPsoGRAPH 2 SHEETS- SHEET 1 Dec. 30, 1952 Filed Jan. 19. 195o` 3 nvcntor (Ittornegs Patented Dec. 30, 1952 UNITED STATES PATENT OFFICE ELLIPSOGRAPH John H. Barker, Watertown, Conn.

Application January 19, 1950, Serial No. 139,470

9 Claims. l

This invention relates to drafting mechanisms for use in producing such geometrical figures as ellipses, elliptical and other curves, circles, and other configurations. Because d-evices of this type are usually employed to produce congurations of an elliptical nature, they are generally known as ellipsographs, and the present invention is so termed in the following description. However, it will be understood that many diierent figures and curves in addition to mathemati-cally correct ellipses can be produced by the present device. Likewise, the invention is not limited to use in operating a scribing or marking device, but is also adapted to guide the movement of such other implements as welding electrodes, or such cutting to-ols as oxyacetylene torches and the like.

An object of the invention is to provide an ellipsograph or similar device having an improved and simplified construction for controlling the movement oi the tool or scriber operating bar.

A further object is to provide a drafting mechanism such as an ellipsograph constructed and arranged to permit its use with such drafting instruments as T-squares, triangles, and so forth, for the purpose of producing a predetermined figure and accurately locate it on a given drawing.

With the foregoing and other objects in view, I have devised the construction illustrated in the accompanying drawings forming a part of this specification. It is, however, to be understood the invention is not limited to the specific details of construction and arrangement shown, but may embody various changes and modifications within the scope of the invention.

A feature of the invention is the provision on a supporting base of a guide bar for a scribing tool, cutting torch or the like, which is slidably mounted in a pair of `supporting blocks, guided for slidingmovement on the'base in a direction at right angles to each other. The base is preierably rectangular with the two guide blocks movable at right angles to each other in directions parallel to the side and top edges. Each side of the base forms in elfect a straight edge. As a result, the invention provides a useful drafting tool which can be used with T-squares, triangles and the like, to accurately and correctly locate the gure being produced on a given drawing. The guide bar is formed with perpendicular arms, one oi which slidably engages each block, and each of which is parallel to one edge of the base. As a result, substantially any compound movement can be imparted tothe bar and such :movement will be accurately defined.

The guide bar is formed with a pair of slots at right angles to each other, each slot being parallel to one edge of the base. As a result, one slot is parallel to one arm of the guide bar and the other slot is parallel to the other arm. A pair of adjustable throw cranks are geared together for simultaneous movement and are connected to the bar so that one crank moves the bar in one perpendicular direction and the other crank in the other perpendicular direction. By varying the crank throws any desired compound movement can be imparted to the guide bar and the supported tool. Means are provided for accurately setting the cranks to predetermined measurements so that the figures produced by moving the guide bar will be accurately dimensioned.

These and other objects and features are accomplished by the present invention. In the accompanying drawing,

Fig. 1 is a plan view of a drafting device constructed in accordance with one embodiment of this invention;

Fig. 2 is a side elevation of the device shown in Fig. l;

Fig. 3 is a perspective view of a detail;

Fig.\4 is a section on an enlarged scale showing further details;

Figs. 5 and 6 are sections on the lines 5-5 and 6 6, respectively, of Fig. 1, and

Fig. '7 is a perspective view of the device shown in Fig. l.

The illustrated embodiment of the invention is shown as an ellipsograph having a base I I with the edges thereof accurately formed at right angles to each other. A guide bar I2 is supported on the base and has arms I3 and I4 perpendicular to each other and slidably mounted in supporting blocks I5 and I6 respectively. One block l5 is generally of inverted T-shape and is slidable in a slot I1 extending along and parallel to one edge of the base II. The other block I6 is of L-shape and is slidable in a slot IB extending along another edge of the base at right angles to the rst slot Il. Hence, the guide bar is universally movable in its plane by a sliding movement laterally of either or both the supporting slide blocks I5 and I6. Each block has top iianges overlapping the top faces of the respective arms I3 and I4 tosnugly retain the arms vin place' in the blocks. The blocks are retainedA in'theirl associated slotsA I1 and I8 by retaining plates 2l and 22 which overlie the slots and engage retaining shoulders 23 on the associated blocks.

Movement is imparted to the guide bar by a handle 2li, and the direction of movement is controlled by a pair of variable throw crank pins 2t and 25 on crank discs or gears 26 and 2 respectively, which are geared together and rotatably supported on the base II on studs 28 and 2Q. @ne crank pin 24 extends through and is movable along a slot 32 formed in the guide bar parallel to one arm I3 thereof. As illustrated, the slot 32 is formed in an arm 33 on the bar which is parallel to the arm I3. The other crank 25 extends through and is movable along a slot :ill parallel to the other arm i4 of the guide bar. As illustrated, this slot is formed directly in the arm Iii. Hence, each crank is employed to move the bar in a direction parallel to one edge of the base II and perpendicular to the direction of movement produced by the other crank.

Each crank pin is radially adjustable on its supporting disk or gear. As illustrated, each crank is adjustable along a radial slot 35 formed on the surface of the associated gear or disk by spaced angle strips l5 secured thereto. Each crank pin has a head 37 located in the slot 35, as best shown in Fig. 6.v A clamping washer 38 loosely surrounds the crank pin above the slotforming strips 35. A clamping Vnut 4I is threaded to each pin `and bears on the end of a sleeve d2 loosely-surrounding each pin and extending freely through the slot in the associated guide bar. The sleeve and washer may be either separate members or integral. The sleeve is suiciently greater in length than the thickness of the guide bar to prevent the nut Il! from clamping the bar. When the nut @I is tightened on the associated crank pin the angle strips 55 will be clamped between the washer 33 and the head 3l whereby the pin will be secured against movement along the radial slot 35 while being freely movable along the slot in the guide arm I2. In order to adjust the position of the crank pin on its gear it is only necessary to loosen the nut 4I and move the pin along the slot 55, after which it can be secured in adjusted position by tightening the nut. t will be understood that in forming an ellipse, for example, the different axes thereof Will be fixed by the distances the two pins are adjusted from the centers of the respective supporting gears. These distances can be accurately fixed in the present invention as hereafter described.

The arm I 3 of the guide bar is shown in Fig. 7 as arranged to hold a scriber 45, but as above pointed out it can be used equally well to hold a cutting torch, welding electrode or any other suitable device, the invention being independent of the particular tool employed.

Assuming, however, that the invention is to be used to draw an "ellipse, the crank pin 24 is adjusted adistance from the center of the supporting disk or' gear 26 equal to one-half the length of one axis of the ellipse. This distance can be accurately'measured on the scale M43 provided for this purpose on the retaining plate 2l. In making this adjustment, the radial slot 35 in which the pin 2li is movable is first positioned parallel to the slot Il in which the bar-supporting block l is mounted and, hence, parallel te one perpendicular edge of the base I l. The scale is so formed that when the pin 2d is aligned with the center of the supporting disk or gear the edge of the block I5 is located at the beginning of the scale. kAdjustment of the pin to the'left in Figs. 1 and 7 can then be accurately measured oi'i` on the scale d3. When properly adjusted, the associated nut is tightened to secure the pin 24 in place. Thereupon, the bar is swung by the handle 20 so as to rotate the other crank disk or gear 21 clockwise and swing the other crank pin 25 in a clockwise direction until the associated radial slot 35 in which this pin is adjustable is parallel with the slot I8 in which the bar-supporting block I6 is slidable and, hence, parallel to another perpendicular edge of the base II. This crank is then adjusted a distance from the center of the associated gear 21 equal to the length of the other axis of the ellipse, and the securing nut for this crank then tightened. This adjustment can be accurately read on the scale 4d on the retaining plate 22 as adjustment of the pin is obtained by shifting the bar in a direction parallel to the slot I8 and thereby moving the block .I 6 in the slot along the scale. When Vthe pin 25 is over the center of the gear 21 the edge of .the 'block I 5 will be located at the beginning .of `the scale and will be moved along the scale as the pin is moved farther from the gear center. Y

When both adjustments are completed and the cla-mping nuts tightened, the desired ellipse can be produced by "moving the scriber bar so as to -rotate the gears 26, 27. The cranks will impart the required'compound movement to the bar to obtain the desired movement of V'the'drawing tool or other implement.

It will beapparent that whatever figure is produced by the v'compound movement, its position and direction can be accurately located on a given drawing by properly positioning the edges of the base II `by means of a T-square, triangle, or other Ydrafting guide. The dimensions of the figure can be accurately Yprefixed and readily changed as needed. v Y

The specific embodiment of the invention herein described can be variously modified and adapted within the scope'o'f the appended claims.

Hav-ing thus set forth the nature oi my invention, 1 claim:

l. An ellipsograph comprising a base member, a guide bar supporting amarking tool or the like comprising arms at right angles to each other, means supporting said bar on said base member for movement in two directions at right angles to each other, .including a bar-supporting block for each arm, said blocks being slidable on said base member in directions at right angles to each other, a pair of variable throw cranks, means connecting one of the cranks to said bar to con-trol the movement of said bar in one directionv and means rconnecting the other crank to the bar to control the movement of the bar in the other direction, and means for shifting said bar.

2. An ellipsograph compri-sing a guide bar, barsupporting blocks movable in directions at right angles to'each otherfor guiding the movements of said bar, said Tear 'being slidable in each block in adirection at vright angles'to the direction of movementio'f the block, a pair of cranks, means connecting each of said cranks 'to said bar for limiting the movement'thereof in one of each of said directions, means for adjusting the effective lengths of the cranks, and means connecting, vsaid cranks for `simultaneous rotation to impart to said bar a compound movement determined by the relative adjustments :of said cranks.

v3. An ellipsograph comprising `a supporting base, .a'pair of 'blocks'movable at rightangles to each other'on the,A base, a guide barslidably supported onsaidblocks, a variable throw crank engaging a slot in said bar extending parallel to the direction .of movement of one block, a second variable throw crank engaging a second slot in said bar extending parallel to the direction of movement of the other block, a scale associated with each block whereby to measure the throw of each of said cranks, and means connecting said cranks together for simultaneous rotation, whereby movement imparted to said bar is controlled and defined by the relative positions of said cranks.

4. A mechanism comprising a base member, a tool-supporting guide bar having arms perpendicular to each other, separate means slidably supporting each of said arms, separate independent guide means on the base for each arm supporting means, the supporting means for each arm being movable on said base in a direction parallel to the other .armand means controlling the movement of the bar in each direction comprising a pair of meshing gears and means connecting each gear to one of the |bars respectively, whereby movement imparted to said bar causes a tool supported thereon to describe a predetermined gure.

5. A mechanism comprising a base member having side edges .perpendicular to each other, a toolsupporting guide bar having arms perpendicular to each other, each arm being parallel to one of said side edges, separate means slidably supporting each arm of said bar, separate independent guide means :on the base for each arm supporting means, the support for one arm being movable on the base in a direction parallel to one of said edges, and the support for the other arm being movable in a direction parallel to said lother edge, and means controlling the movement of the bar in each direction comprising a pair of meshing gears and means connecting each gear to one of the bars respectively, whereby movement imparted to said bar causes a tool supported thereon to describe a predetermined figure.

6. A mechanism comprising a base member having side edges perpendicular to each other, a tool supporting guide bar having a pair of arm-s each perpendicular to the other and parallel with one of said edges, a block slidably supporting one arm and movable on said base member parallel to one side edge, a second block slidably supporting the Aother arm and movable on said base member parallel to a side edge at right angles to said iirst edge, a variable throw crank engaging a slot in said bar parallel to one arm, a second variable i throw crank engaging a second slot in said bar parallel to said other arm, whereby movement of the guide bar With the throw of said cranks causes said blocks to move on said base member.

and means on said base member cooperating with q each said blocks for relative movement in a direction perpendicular to the `direction of movement of the block, a pair of meshing gears, adjustable means mounted on one of said gears to control the movement of said bar in one of said directions, and adjustable means mounted on the other gear to control movement of said bar in the other of said directions, whereby movement imparted to said bar by rotation of the gears causes a tool supported thereon to produce a figure of predetermined shape and size.

8. A drafting mechanism comprising a supporting base, a tool-'supporting guide bar having two arms perpendicular to each other, a pair of barsupporting blocks mounted :on said base for movement at right angles to each other, each arm slidably engaging one of said blocks for relative movement in a direction perpendicular to the direction of movement of the block on said base, a pair of meshing gears mounted on the base, adjustable means mounted on one of said gears to control the movement of said bar in one yof said directions, and adjustable means mounted on the other gear to control movement of said bar in the other of said directions whereby movement imparted to said bar by rotation of the gears causes a tool supported thereon to produce a figure of predetermined shape and size.

9. A drafting mechanism comprising a toolsupporting guide bar having -two arms perpendicular to each other and a pair of slots one parallel to each arm, a base member, a pair of bar-supporting blocks mounted for movement at right angles to each other on said base member, each arm slidably engaging one of said blocks for relative movement in a direction perpendicular to the direction of movement of the block, and a separate adjustable throw crank engaging in each slot, and means connecting said cranks for simultaneous rotation, whereby movement imparted to said bar causes a tool supported thereon to produce a figure of predetermined shape and size.

JOHN H. BARKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 296,100 Abbott Apr.. 1, 1884 456,105 Adams July 14, 1891 511,772 Harrer Jan. 2, 1894 492,142 Corkhll Feb. 21, 1895 1,163,392 Cashmore Dec. 7, 1915 1,284,884 Foster Nov. 12, 1918 1,485,258 Dzus Feb. 26, 1924 FOREIGN PATENTS Number Country Date 636,233 Germany Oct. 5, 1936 

